Delta 4000
| Launch of a Delta 4925 | |
| Function | Launch vehicle | 
|---|---|
| Manufacturer | McDonnell Douglas | 
| Country of origin | United States | 
| Cost per launch | US$34.22 million in 1985 (4925 variant) (US$79.99 million in 2018) | 
| Size | |
| Height | 34 m (112 ft) | 
| Diameter | 2.44 m (8 ft 0 in) | 
| Mass | 200,740 kg (442,560 lb) | 
| Stages | 2 or 3 | 
| Capacity | |
| Payload to LEO | |
| Mass | 3,400 kg (7,500 lb) | 
| Payload to GTO | |
| Mass | 1,200 kg (2,600 lb) | 
| Associated rockets | |
| Family | Delta | 
| Comparable | Delta 5000, Delta II | 
| Launch history | |
| Status | Retired | 
| Launch sites | Cape Canaveral SLC-17 Vandenberg AFB SLC-2W | 
| Total launches | 2 | 
| Success(es) | 2 | 
| First flight | 28 August 1989 | 
| Last flight | 12 June 1990 | 
| Boosters – Castor 4A | |
| No. boosters | 9 | 
| Height | 9.12 m (29.9 ft) | 
| Diameter | 1.02 m (3 ft 4 in) | 
| Empty mass | 1,529 kg (3,371 lb) | 
| Gross mass | 11,743 kg (25,889 lb) | 
| Powered by | Solid | 
| Maximum thrust | 478.3 kN (107,500 lbf) | 
| Specific impulse | 
 | 
| Burn time | 56 s | 
| First stage – Thor/Delta ELT | |
| Height | 22.4 m (73 ft) | 
| Diameter | 2.44 m (8 ft 0 in) | 
| Empty mass | 4,059 kg (8,949 lb) | 
| Gross mass | 84,067 kg (185,336 lb) | 
| Powered by | 1 MB-3 | 
| Maximum thrust | 760.6 kN (171,000 lbf) | 
| Specific impulse | 
 | 
| Burn time | 222 s | 
| Propellant | LOX / RP-1 | 
| Second stage – Delta K | |
| Height | 5.89 m (19.3 ft) | 
| Diameter | 2.44 m (8 ft 0 in) | 
| Empty mass | 950 kg (2,090 lb) | 
| Gross mass | 6,954 kg (15,331 lb) | 
| Powered by | 1 AJ10-118K | 
| Maximum thrust | 43.6 kN (9,800 lbf) | 
| Specific impulse | 319 s | 
| Burn time | 431 s | 
| Propellant | N2O4 /Aerozine 50 | 
| Third stage – PAM-D (optional) | |
| Height | 2.03 m (6 ft 8 in) | 
| Diameter | 1.25 m (4 ft 1 in) | 
| Empty mass | 128 kg (282 lb) | 
| Gross mass | 2,137 kg (4,711 lb) | 
| Powered by | Star 48B | 
| Maximum thrust | 66 kN (15,000 lbf) | 
| Specific impulse | 286 s | 
| Burn time | 87 s | 
The Delta 4000 series was an American expendable launch system which was used to conduct two orbital launches in 1989 and 1990. It was a member of the Delta family of rockets. Although several variants were put forward, only the Delta 4925 was launched. The designations used a four digit numerical code to store information on the configuration of the rocket. It was built from a combination of spare parts left over from earlier Delta rockets, which were being retired, and parts from the Delta II 6000-series, which was just entering service.